1. Field of the Invention
The present invention relates to stretchable insulation fabrics which are particularly useful in thin, close-fitting garment applications.
2. Background Information
A wide variety of natural and synthetic filling materials or thermal insulation applications, such as in outerwear, e.g., ski jackets and snowmobile suits, sleeping bags, and bedding, e.g., comforters and bedspreads, are known.
Natural feather down has found wide acceptance for thermal insulation applications, primarily because of its outstanding weight efficiency and resilience. However, down compacts and loses its insulating properties when it becomes wet and exhibits a rather unpleasant odor when exposed to moisture. Also a carefully controlled cleaning and drying process is required to restore the fluffiness and resultant thermal insulating properties to a garment in which the down has compacted.
There have been numerous attempts to prepare synthetic fiber-based substitutes for down which could have equivalent thermal insulating performance without the moisture sensitivity of natural down.
U.S. Pat. No. 4,065,599 (Nishiumi et al.) discloses synthetic filler material comprising spherical objects made up of filamentary material comprising spherical objects made up of filamentary material with a denser concentration of filaments near the surface of the spherical object than the filament concentration spaced apart from the surface.
U S. Pat. No. 4,118,531 (Hauser) discloses a thermal insulating material which is a web of blended small denier fibers with crimped bulking fibers which are randomly and thoroughly intermixed and intertangled with the small denier fibers. The crimped bulking fibers are generally introduced into a stream of blown small denier fibers prior to their collection. This web combines high thermal resistance per unit of thickness and moderate weight.
U.S. Pat. No. 4,259,400 (Bolliand) discloses a fibrous padding material simulating natural down, the material being in the form of a central filiform core which is relatively dense and rigid and to which are bonded fibers which are oriented substantially transversely relative to this core, the fibers being entangled with one another so as to form a homogeneous thin web and being located on either side of the core, substantially in the same plane.
U.S. Pat. No. 4,392,903 (Endo et al.) discloses a thermal insulating bulky product which has a structural make-up of substantially continuous, single fine filaments of from about 0.01 to about 2 denier which are stabilized in the product by a surface binder. Generally, the binder is a thermoplastic polymer such as polyvinyl alcohol or polyacrylic esters which is deposited on the filaments as a mist of minute particles of emulsion before accumulation of the filaments.
U.S. Pat. No. 4,418,103 (Tani et al.) discloses the preparation of a synthetic filling material composed of an assembly of crimped monofilament fibers having crimps located in mutually deviated phases, which fibers are bonded together at one end to achieve a high density portion, while the other ends of the fibers stay free.
U.S. Pat. No. 4,588,635 (Donovan) describes thermal insulating materials which are batts of plied card-laps of a blend of 80 to 95 weight percent of spun and drawn, crimped, staple, synthetic polymeric small denier fibers having a diameter of from 3 to 12 microns and 5 to 20 weight percent of synthetic polymeric staple macrofibers having a diameter of from more than 12, up to 50 microns.
U.S. Pat. No. 4,618,531 (Marcus) discloses polyester fiberfill having spiral-crimp that is randomly arranged and entangled in the form of fiberballs with a minimum of hairs extending from their surface, and having a refluffable characteristic similar to that of down.
U.S. Pat. No. 4,438,172 (Katsutoshi et al.) discloses a heat retaining sheet comprising at least a web in which fibers containing polybutylene terephthalate as at least one of their components and having a substantially undrawn definite fiber length are mutually bonded, and which has small area shrinkage in boiling water. The sheet is described as having excellent durability and heat retaining properties as well as being elastic with an especially high stretch recovery ratio and very soft and flexible.
U.S. Pat. No. 4,551,378 (Carey, Jr.) discloses a nonwoven thermal insulating stretch fabric which is produced from a web of bicomponent fibers bonded together by fusion of fibers at points of contact and thermally crimped in situ in the web. The fabric is described as having good uniformity, good thermal insulating properties.
U.S. Pat. No. 4,660,228 (Ogawa et al.) discloses a glove comprising two elastic sheet materials, at least one of which consists essentially of a selected elastic polyurethane nonwoven fabric which is relatively thin, elastic, air and moisture permeable, dimensionally and texturally stable, nonslip and dustproof. The polyurethane nonwoven fabric is obtained by a melt-blowing process.
U.S. Pat. No. 4,600,605 (Nakai) discloses a stretchable wadding with an apparent density of 0.005 to 0.05 g/cm.sup.3 which is formed from a web of crimp potential fibers bonded together and shrunk by drying. The crimp potential fibers are preferably bonded to each other by spraying an adhesive onto the web and drying the adhesive before shrinking the fibers by drying. The fibers may also be needled before the adhesive is applied.
Ogawa, in an article entitled "Development of Spunbonded Based on Thermoplastic Polyurethane," Non-wovens World, May-June, 1986. pp 79-81, describes a spunbonded nonwoven polyurethane elastic fabric developed by Kanebo Ltd. The fabric is made using a melt blown process which is different from a conventional melt blown process to produce fabric which is similar to that of spunbonded fabrics. The diameter of its filaments is not so fine as that of the usual melt blown fabrics, i.e., 0.5-2 micrometers, but apparently is closer to that of the spunbonded fabrics, i.e., 20-50 micrometers. The elasticity, dust catching capability, low linting, high friction coefficient, air permeability and welding characteristics of the urethane fabrics are discussed in the article.